As those of you who live in or around Montreal know, there has been a huge influx of migrating Painted Lady butterflies this summer / fall.
The last time this happened was in 2012 but I think the thousands of butterflies this year out-number that previous irruption (definition: a sudden sharp increase in the relative numbers of a natural population usually associated with favorable alteration of the environment)!
The Montreal Gazette published the following article:
SEPTEMBER 18, 2017
The thousands of orange butterflies being spotted all over Montreal are simply on a rest stop as they make their way down south.
And 99 per cent of them are painted ladies and not the monarch butterfly, said Maxim Larrivée of the Montreal Insectarium.
There has been some confusion over what type of butterflies were being spotted because of the colour patterns, but there are clear differences between painted ladies and monarchs, said Stephanie Boucher, curator at McGill University’s Lyman Entomological Museum.
“The painted lady butterfly is not as well known as the monarch, so that is probably why most people identify it as what they know best,” Boucher said.
“What’s really unusual is how many there are, which is really unprecedented,” Larrivée said, adding that this is the second time it happened in five years.
He said he believes they got pushed to the ground by wind during their migration to the warmer Southern U.S. climates from the Boreal Shield area. But they generally don’t stick around this long.
“But we have had this spell of amazing weather for us, that is not great migration weather for them. In the meantime, they are fuelling up on flowers, this is why we are seeing them (drinking nectar) everywhere,” Larrivée said.
Larrivée and Boucher both said the painted ladies benefit from the fact they can feed on a wide variety of plants — up to 100 according to Boucher — compared with the monarch, which feeds on milkweed.
“They can adapt to many different type of plants, so that is a great advantage,” she said.
Larrivée said the butterflies enjoyed a great winter in terms of reproduction in areas like Texas, New Mexico, Arizona and northern Mexico. They then migrated north earlier than usual, arriving in mid-April and he thinks that gave them the time to have an extra generation, reproducing twice instead of once during the summer.
“The population was probably already big when they started coming north,” Boucher said. “The year here was also a good one for them for breeding and reproducing with all the rain we got.”
Now with everyone being outside thanks to the great weather, they are being spotted everywhere.
“It’s pretty hard to be in a bad mood when you are surrounded by butterflies. It’s fantastic. It’s different,” Larrivée said.
Now they are waiting for “winds that they are going to be able to surf back to the south,” Larrivée said, ideally blowing from the northeast to the southwest.
By Kevin Mio, Montreal Gazette.
Here is a selection of photographs that I have taken in various areas on the island of Montreal in the last few weeks: